Ultra-violet protective light filter



Oct 11, 1966 D. LAUERER ETAL 3,278,448

ULTRA-VIOLET PROTECTIVE LIGHT FILTER Filed May 17, 1960 f l 700 500 500400 350 300 250 200m IN V EN TORS DOPOTHEA LAUEFPER, MAX PESTEMER MAXCOENEN,

GUSTAV BUCHWALD. "M 3, C7

A TTORNEY United States Patent ULTRA-VIOLET PROTEQTHVE LIGHT FILTERDorothea Lauerer, Cologne-Stammheim, Max Pestemer,

Gpladen, Max (Ioenen, Gruiten, Rhineland, and Gustav Buchwald,Krefeld-Bockum, Germany, assrgnors to li arbentabrilren BayerAlrtiengesellschaft, Leverkusen,

Germany, a corporation of Germany Filed May 17, 1960, Ser. No. 29,719Claims. (Cl. 252-300) The present invention relates to ultra-violetlight filters. Compounds absorbing ultra-violet rays are used to protectsubstances which are sensitive to light such as foodstuffs, dyestufis,wood pulp, paper, plastics, fibrous materials and like materials againstultra-violet radiation either by admixing them directly with thesubstance to be protected or by incorporating them into a light-pervioussupport layer which is placed between the substance to be protected andthe source of radiation, for instance light. The absorption of theultra-violet light must start close up to the limit of the visible andultra-violet range of the spectrum at 400 m, so that the visible rangecan pass through without hindrance to avoid discoloration, where as theultra-violet range of rays is substantially absorbed. The filter mediaemployed to protect the said light sensitive substances are thereforerequired to absorb light of higher wavelengths than the knownskin-protecting agents which are to allow the ultra-violet light rays ofhigh wave lengths (i.e. the range between 4-00 and 330 m to pass throughas far as possible, since the aforesaid range contains theskin-pigment-forming rays. In order to guarantee complete protection forlight sensitive substances the aforesaid range of 400 to 330 m must beabsorbed. Besides, the compounds absorbing the ultra-violet rays are tobe fast (or at least substantially fast) to light, since they have to beexposed to strong radiation. Moreover, they must not show an appreciablefluorescent effect, since fluorescent light brings about an opaqueimpression in the support layers.

In accordance with the present invention it has been found that theaforesaid conditions are satisfied to an excellent degree by usingcompounds of the general formula These compounds are, therefore, veryuseful as compounds absorbing ultra-violet rays. In the aforesaidformula, Ar denotes a phenyl radical which is substituted by one or morehydroxy groups or alkoxy groups and optionally by further groups such asfor example halogen (chlorine, bromine) or alkyl groups; R is CN, COOH,COX (CH -CO0H, (CH COOR; R is H, alkyl, CN, COX, COOH; X stands foropitionally substituted alkyl or aryl radicals, primary, secondary ortertiary amino groups or alkoxy groups; R is hydrogen, alkyl-, aralkyl,aryl-, amino-, substituted amino-, hydroxy-, alkoxy-, mercapto-,alkylmeroaptogroups; and n means an integer from 1 to 4.

Alkyl groups are preferably such containing up to 12 carbon atoms. Asexamples of compounds used according to the invention there may bementioned:

Patented Oct. 11, 1966 "ice 4-hydroxy-cinnamic acid 4-hydroxy-cinnamicacid methyl or ethyl ester 4-hydroxy-u-carbethoxy-cinnamic acid ethylester 4-hydroxy-a-cyano-cinnamic acid ethyl ester4-hydroxy-a-cyano-cinnamic acid nitrile 4-hydroxy-a-acetyl-cinnamic acidanilide 4-hydroxy-a-phenyl-cinnamic acid 2-hydroxy-u-diacetylstyreneZ-hydroxy-wanisoyl-cinnamic acid ethyl esterZ-hydroxy-oi-phenyl-cinnamic acid nitrile4-hydroxy-3-*nethoxy-u-diacetylstyrene4-hydroxy-3-methoxy-u-acetyl-cinnarnic acid ethyl ester 4-hydroxy-3-rnethoxy-a-acetyl-cinnamic acid anilide3-hydroxy-4-methoxy-a-acetyl-cinnamic acid ethyl ester3-hydr0xy-4-methoxy-a-phenyl-cinnamic acid ethyl esterZ-hydroxy-B-methoxy-a-diacetylstyrene2-hydroxy-3-methoxy-a-acetyl-cinnamic acid ethyl ester 2hydroxy-3-methoxy-ot-anisoyl-cinnamic acid ethyl ester4-hydroxy-3,5-di-tert.-butyl-a-carbethoxy-cinnamic acid ethyl ester4-hydroxy-3,S-di-tert.-butyl-u-cyano-cinnarnic acid ethyl ester(M.P.:993 C.) 4hydroxy-3,S-di-tert.-butyl-a-cyano-cinnamic acid nitrile1- [4-hydroxy-3-methoxyphenyl] -3-oxo penta-en( 1,2)

S-carb-onic acid 2-hydroxy-3,S-dichloro-a-acetyl-cinnamic acid ethylester 4-methoxy-a-cyano-cinnamic acid nitrile4-hydroxy-B-methyl-a-cyano-cinnamic acid nitrile4-hydr0xy-B-me-thyl-tt-carbmethoxy-cinnamic acid methyl ester4-hydroxy-fl-methyl-a-cyano-cinnamic acid methyl or ethyl ester4-methoxy-,8-methyl-a-cyano-cinnamic acid methyl ester4-methoxy-fl-methyl-a-cyano-cinnamic acid amide4-methoxy-B-methyl-u-cyano-cinnamic acid nitrile4-hydroxy-phenyl-fi-methyl-a-acetyl-cinnamic acid ethyl ester or theiramide a-cyano-p-hydroxy-cinnamic acid nitrile4-methoxy-3-chloro-a-cyan*o-/3-methoxy-cinn-amic acid nitrilea-cyano-fi-amino-cinnamic acid nitrile a-cyano-B-(phenylamino) -cinnamicacid nitrile a-cyano-fi-(cyclohexylamino)-cinnamic acid nitrile4-methoxy-3-chloro-a-cyano-,B-rnethyl-rnercapto-cinnamic acid nitrileNear 400 III/1. the absorption spectra of all these compounds show asteep gradient of the absorption curve the lowest branches of whichextend only into the visible range of wavelength. Thus, the substancesof the invention are only slightly yellowish which is no longerperceptible after incorporating the substances into the materials to beprotected for instance foils or lacquers at a concentration of less than0.5% by weight referred to the solid substance. The quantities of thecompounds to be used according to the invention depend i.a. for instanceon the thickness of the layer used and can easily be determined bypreliminary tests.

Since even under the influence of long exposure in sunlight, thesecompounds are not changed chemically and discolored, not only is thematerial into which it is incorporated protected for a long time againstthe effect of ultra-violet rays, but also the material disposedunderneath this material is protected from the damaging influence oflight which contains ultra-violet portions before passing through thematerial. Owing to these advantageous properties, the compounds aresuitable for a wide range of different purposes, such for example as aprotective means for cotton or other natural products such as forcoating, films, foils, threads, fibres, molded articles or other shapedelements consisting of synthetic plastics, for preventing or delayingthe bleaching of dyeing on textile materials, as an additive toprotective and filter layers for light-sensitive photographic films andpapers as well as for photographic images and as additive to packingmaterials for light-sensitive goods or to lacquer.

In the accompanying diagrammatic drawing there are illustrated theabsorption curves of some compounds according to the invention. Theabsorption culves are obtained by using the following compounds:

Curve 1: 4-hydroxy-B-methyl-a-cyano-cinnamic acid nitrile.

Curve 2: 4-hydroxy-fi-methyl-a-cyano-cinnamic acid methyl ester.

Curve 3: 4methoxy-,8-methyl-a-cyano-cinnamic acid methyl ester.

Curve 4: 4-hydroxy-fl-methoxy-u-diacetylstyrene.

The invention is further illustrated by the following examples, whereinthe parts given are parts by weight.

EXAMPLE 1 15 parts of ethyl cellulose and parts of d'ammar (free of wax)are dissolved in 60 parts of toluene. 0.15 part of4-hydroxy-a-aoetyl-cinnamic acid anilide is added. After the solutionhas been cast and after the solvent has evaporated, there is obtained acolorless, water-insoluble film which provides protection againstultra-violet rays and does not turn yellow in sunlight. Otherfilm-forming agents, for example nitro-cellulose, can be used instead ofethyl cellulose.

EXAMPLE 2 3 mols of maleic acid anhydride, 7 mols of phthalic acidanhydride and 10 mols of ethylene glycol are esterified in known manner.The resulting unsaturated polyester resin is mixed with monostyrene atthe ratio 3:1. 0.25 part of p-hydroxy-a-cyano-B-methyl-cinnamic acidethyl ester are added per 100 parts of the solution. After the additionof 2% benzoyl peroxide the polyester resin thus stabilized to light ispolymerized at 60 C. for 4 hours. In contradistincti'on tonon-stabilized polyester resins, the test samples obtained do not showany discoloration after exposure to a mercury-vapour lamp for 200 hours.

EXAMPLE 3 When using in Example 2 the p-methoxy-derivative instead ofp-hydroxya-cyano-B-methyl cinnamic acid ethyl ester, the test samplesobtained therewith show an equally good stabilizing eflect againstultra-violet radiation.

EXAMPLE 4 A commercial cellulose ester lacquer to which 0.5% of itsweight of a-cyano-}8-phenyleue-amino-cinnamic acid nitrile was added, isapplied by brushing onto sheet metal and exposed to a mercury-vapourlamp for 12 hours. In contra-distinction to a control coating which isnot provided with a protective agent, the coating obtained according tothe invention does not show any substantial yellowing.

What is claimed is:

1. A light filter for protecting substances from ultraviolet radiation,inclusive of light within the range of 330 Inn-400 m the filterconsisting essentially of a light pervious support layer havingincorporated therewith a substantial light absorbing amount of acompound having the formula wherein Ar is a phenyl substituted by amember selected from the group consisting of hydroxy, alkoxy, and, whendesired, at least one additional substituent selected from the groupconsisting of halogen and alkyl; R is a member selected from the groupconsisting of CN, COOH, COX, (CH L COOH and (CH ),,COOR, wherein R islower alkyl; R is a member selected from the group consisting of H,alkyl, CN, COOH and COX, wherein X is a member selected from the groupconsisting of an alkyl, aryl, amino, and alkoxy; R is a member selectedfrom the group consisting of an alkyl, amino, hydroxy, alkoxy, mercaptoalkyl mercapto; and n is a whole number of 1-4.

2. Ultra-violet protective light filter consisting of a film-formingcomposition having incorporated therein, in an amount sufiicient tosubstantially absorb radiation in the range of 330 m -400 mu, consistingof a film-forming composition having incorporated therein, in an amountsufiicient to absorb ultra-violet rays, 4-hydroxy-phenyl-{3-methyl-a-cyano-cinnamic acid nitrile.

3. Ultra-violet protective light filter consisting of a film-formingcomposition having incorporated therein, in an amount sufficient tosubstantially absorb radiation in the range of 330 Inn-400 mu,consisting of a film-forming composition having incorporated therein, inan amount sufiicient to absorb ultra-violet rays, 4-hydroxy-phenyl-l3-methyl-m-cyano-cinnamic acid methyl ester.

4. Ultra-violet protective light filter consisting of a film-formingcomposition having incorporated therein, in an amount sufficient tosubstantially absorb radiation in the range of 330 mu-400 mu, consistingof a film-forming composition having incorporated therein, in an amountsufiicient to absorb ultra-violet rays, 4-methoxy-phenyl-p3-methyl-a-cyano-cinnarnic acid methyl ester.

5. Ultra-violet protective light filter consisting of a film-formingcomposition having incorporated therein, in an amount sufiicient tosubstantially absorb radiation in the range of 330 m -400 ma, consistingof a film-forming composition having incorporated therein, in an amountsufficient to absorb ultra-violet rays,4-hydroxy-phenyl-fimethoxy-u-diacetylstyrene.

6. A method for protecting and stabilizing a substance from ultra-violetlight, inclusive of light within the wave length 330 m,u400 m consistingin incorporating into said substance, and, when desired, into a lightpervious support layer interposed between said substance and anultra-violet light source, a substantial light-absorbing amount of acompound having the formula Rs R:

AIC=C R2 wherein Ar is a phenyl substituted by a member selected fromthe group consisting of hydroxy, alkoxy and, when desired, at least oneadditional substituent selected from the group consisting of halogen andalkyl; R is a member selected from the group consisting of CN, COOH,COX, (CH ),,.COOH and (CH ),,COOR, wherein R is lower alkyl; R is amember selected from the group consisting of H, alkyl, CN, COOH and COX,wherein X is a member selected from the group consisting of an alkyl,aryl, amino, and alkoxy; R is a member selected from the groupconsisting of an alkyl, amino, hydroxy, alkoxy, mercapto alkyl mercapto,and n is a whole number of 1-4.

7. A method according to claim 6 wherein said incorporated compound is4-hydroxy-phenyl-,B-methyl-11- cyano-cinnamie acid nitrile.

8. A method according to claim 6 wherein the compound is4-hydroxy-phenyl-fl-methyl-a-cyano-cinnamic acid methyl ester.

9. A method according to claim 6 wherein the compound is 4methoxy-phenyl-;8-methyl-a-cyano-cinnamic acid methyl ester.

10. A method according to claim 6 wherein the compound is4-hydroxy-phenyl-fl-methoxy-a-diacetylstyrene.

(References on following page) References Cited by the Examiner UNITEDSTATES PATENTS 4/ 1948 Blout et a1 252-300 1/ 1963 Strobel et a1.

FOREIGN PATENTS 12/1959 Canada.

7/1938 Germany.

6 OTHER REFERENCES Plaisted, Contributions From Boyce ThompsonInstitute, v01. 18, No. 5, October-December 1955, pages 231-234.

MORRIS LIEBMAN, Primary Examiner.

JOHN H. MACK, JOSEPH R. LIBERMAN, JOHN R. SPECK, A. LIEBERMAN, R. D.EDMONDS,

Assistant Examiners.

Notice of Adverse Decision in Interference In Interference No. 95,964involving Patent No. 3,278,448, D. Lauerer, M. Pestemer, M. Coenen andG. Buchwald, ULTRA-VIOLET PROTEC- TIVE LIGHT FILTER, final judgmentadverse to the patentees was rendered July 1, 1969,21s to claims 1, 2, 6and 7.

[Ofiiez'al Gazette September 2, 1969.]

Notice of Adverse Decision in Interference In Interference No. 95,964involving Patent No. 3,278,448, D. Lauerer,

M. Pestemer, M. Coenen and G. Buchwald, ULTRA-VIOLET PROTEC- TIVE LIGHTFILTER, final judgment adverse to the patentees was rendered July 1,1969, as to claims 1,2,6 and 7.

[OfiCial Gazette September 2, 1.969.]

1. A LIGHT FILTER FOR PROTECTING SUBSTANCES FROM ULTRAVIOLET RADIATION,INCLUSIVE OF LIGHT WITHIN THE RANGE OF 330M$-400M$, THE FILTERCONSISTING ESSENTIALLY OF A LIGHT PERVIOUS SUPPORT LAYER HAVINGINCORPORATED THEREWITH A SUBSTANTIAL LIGHT ABSORBING AMOUNT OF ACOMPOUND HAVING THE FORMULA